1. Field of the Invention
The present invention relates to a method for manufacturing a display device, using a printing method.
2. Description of the Related Art
In a thin film transistor (hereinafter also referred to as a TFT) and an electronic circuit using the thin film transistor, various thin films such as a semiconductor film, an insulating film, and a conductive film are stacked over a substrate, and they are appropriately formed into predetermined patterns by a photolithography technique. The photolithography technique is a technique in which a pattern of a circuit or the like which is formed using a material that does not transmit light over a transparent flat plate, which is referred to as a photomask, is transferred to an aimed substrate by using light. The photolithography technique is widely used in a manufacturing process of a semiconductor integrated circuit and the like.
The conventional manufacturing process using the photolithography technique requires multiple steps such as exposure, development, baking, and peeling only for treating a mask pattern formed by using a photosensitive organic resin material that is referred to as a photoresist. Therefore, the manufacturing cost is inevitably increased as the number of the photolithography steps is increased. In order to solve this problem, it has been attempted to manufacture TFTs with the lower number of photolithography steps (refer to Patent Document 1: Japanese Published Patent Application No. 2000-133636). In Patent Document 1, a resist mask formed in a photolithography step is used once, and then reused as a resist mask having a different shape by expanding its volume by swelling.